Here’s the abstract from the report:
Pagosa Springs, Colorado is famous for the hydrothermal activity in its groundwater system, though the system is poorly understood. At present, the hot water flow is used for both tourism and the heating of some buildings, but further expansion of the springs’ usage could reduce the effective energy produced in both cases. To better understand the nature and extent of the hydrothermal flow, several geophysical methods were designed and implemented, including: Gravity, magnetics, electromagnetics, seismic, Direct Current (DC) resistivity, and ground penetrating radar (GPR), all of which were tied in with global positioning system (GPS) data. The surveys were designed to determine the structural geology, the locations of water sources, and the direction and magnitude of that flow. These geophysical surveys were employed to give students a better understanding of geophysical methods as well as assisting Pagosa Springs in learning more about the complexion of the springs so as to better utilize the hydrothermal energy without damaging, and hopefully improving, the existing infrastructures.
The data of the geophysical methods was processed, interpreted and integrated by students to attain a plausible explanation of the results and the geothermal system the results describe. At the Stevens Airport and the Barn 3, a survey site far to the south of town, it was shown that the Eightmile Mesa Fault, as well as nearby faults, likely penetrate into the basement geology which could provide a conduit for deep hot water transport. At another site three kilometers south of Pagosa where there were geothermal springs cooler than the Pagosa springs, the data entertains the possibility that there is water flowing from the ridge to the east toward the river to the west. The data also shows that there is likely a fault to the east of the Pagosa Mother Spring. The Pagosa Mother Spring is the main spring in the town that was measured to be at least 1,000 feet deep. Closer to the Mother Spring, on the field southwest and east of the river, the flow of water in the subsurface near the spring was surveyed. Two conduits were expressed in the data: one running east-west and the other going north-south. Finally, one line indicated the possibility of two additional faults north of Pagosa, though further investigation is necessary to better define these results. These integrations can be used to sum up a plausible explanation of the hydrothermal system, however, there are several studies that could still be done in this area to better understand the hydrothermal system as well as hopefully improve the current geothermal usage in Pagosa.
From the Pagosa Sun (Jim McQuiggin):
Earlier this month, the Colorado School of Mines Geophysics Department (CSM) released results of research recently conducted throughout the area. After spending two weeks in Pagosa Country this past May, studying characteristics of the area’s geothermal aquifer, a team of CSM students and faculty members provided a lengthy report on findings during that visit.
The full report can be downloaded at http://geophysics.mines.edu/GEO-Field-Camp.
While not quite as exciting as the almost certain discovery of the Higgs boson that was announced on Tuesday, the report provided some interesting suggestions regarding geothermal resources in the area. Primary among the findings was a suggestion of geothermal resources far more extensive than had been previously postulated.
That report indicated the discovery of three previously unknown faults north, south and west of the “Mother” spring (the Great Pagosa Hot Springs that provides water for local bathers and heating systems).
“First, the seismic results from both the Stevens Airport and the Barn 3 (south of town) line show that the Eightmile Mesa Fault, and possibly other faults nearby, penetrates the basement material,” the report reads. This discovery shows that faults in the area can penetrate the basement (several layers of strified rock that sit atop the water) and provide a conduit for deep and hot water transport.
More geothermal coverage here and here.